Added documentation for printing associated queries, and sample documents in notification message.

[AWSHurneyt]

trafficstars

Description

1. Changed the examples to access items in ctx arrays from using brackets (e.g., itemList[0]) as mustache template uses dot notation (e.g., itemList.0).
2. Added documentation for associated_queries, and sample_documents variables added to the ctx object.

Implementation PR for reference - https://github.com/opensearch-project/alerting/pull/1450

Issues Resolved

https://github.com/opensearch-project/alerting/issues/1300 https://github.com/opensearch-project/alerting/issues/1396 https://github.com/opensearch-project/alerting/issues/1401

Checklist

• [x] By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and subject to the Developers Certificate of Origin. For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[AWSHurneyt]

Draft discussion forum post - https://forum.opensearch.org/t/alerting-sample-documents-for-ctx-dedupedalerts-and-ctx-completedalerts/18695

[hdhalter]

Thanks so much for adding this content, @AWSHurneyt! Is it ready for a doc review?

[AWSHurneyt]

Thanks so much for adding this content, @AWSHurneyt! Is it ready for a doc review?

@hdhalter Yes, this can be reviewed. I actually have a few other updates I was considering adding to this PR as well. We're still waiting for final approval though, so I'll just create a separate PR for them. Those updates would have be unrelated to the feature described in these doc changes; so it's probably for the best to keep them separate.